Preparation of new therapeutically useful heterocyclic compounds



Patented Feb. 23, 1943 UNITED STATES PATENT OFFICE,

v PREPARATION OF NEW THERAPEUTICALLY USE\FUL HETEROCYCLIG COMPOUNDS Arthur James Ewins, Gidea Park, Romford, and

Montague Alexander Phillips, Romford, England, assignors to May & Baken. Limited, London, England, a company of Great Britain and Northern Ireland No Drawing.

Original application November 1,

1938, Serial No. 238,164. Divided and this application April 19, 1940, Serial No. 330,528. In 1 Great Britain, Australia, India, and New Zea- 1 land November 29, 193'! 4 Claims. (Cl. 20295) in which It represents a heterocyclic nucleus of the pyridine, quinoline or isoquinoline series and in which R1 may be hydrogen, acyl, aim], aryl or aralkyl, and R: may be hydrogen or alkyl and R3 may be hydrogen, alkyl, aryl, arallgvl or acyl.

According to the present invention these compounds may be prepared by various methods which may be summarised as follows:

A. Derivatives in which RiRa and R3 are hydrogen atoms may be prepared by condensing a compound of the type p-xCeH4Y with a compound of the type ZR in which R is a pyridine, quinoline or isoquinoline residue, and when Y is SOaCl, X is NH: and when Y is SOaNHa Z is a halogen, to form compounds of the type XC6H4SO2NHR which can be readily converted into compounds of the type NH2C6H4SO2NHR. X therefore represents a group such as an acylamino group, a nitro group, an azo group linked to an organic radicle, or a halogen, which groups may be converted into an amino group by hydrolysis in the first mentioned case, by reduction in the secondand third-mentioned cases, or by the action of ammonia in the fourth case.

B. Similarly, derivatives in which R1 and R2 are hydrogen atoms, and R: an aryl, alkyl, or aralkyl group may be prepared by condensation of compounds of the type 'p-XCsI-LY with compounds of the type ZR in which when Y is SOzQl. Z is NHR3 and when Y is SOzNHRs, Z is a halogen to form compounds of the type p-XC6H4SO2NRaR from which the required amino products may be obtained as described in paragraph A.

C. Derivatives in which R1 is hydrogen or an alkyl or acyl group, R2 is an alkyl, aryl, or aralkyl group and R3 is either hydrogen or, an alkyl, aryl, or aralkyl group may be prepared by condensing a compound of the type R1R2N.C6H4Y with a compound of the type ZR in which R is the residue of a pyridine, quinoline or isoquinoline base, and when Y is SOaCl, Z is NHR: and

when Y is SOzNHRa, Z is a halogen.

D. Derivatives in which R1 is a hydrogen or alkyl, R2 is an alkyl, and R3 is hydrogen or an allwl, aryl or aralkyl group may be prepared from condensation products of the types described in A and B in which X is a halogen by reacting on the respective halogenated condensation products with a primary or secondary amine instead of with ammonia.

E. Acyl, alkyl, aryl or aralkyl derivatives of compounds preparedby the foregoing methods containing one or more replaceable hydrogen atoms attached to nitrogen may be prepared by.

known methods such as by'the use of acyl, alkyl, aryl, or aralkyl halides or alkyl sulphates.

Besides using compounds of the type -xcemsozci various chemically equivalent processes may be used instead, such as the use of the anhydrides (D-X.CsH4SO2)2O or the bromides The following examples illustrate how the invention may be carried out in practice, but it is to be understood that the invention is in no way limited to the details given in these examples:

Example 1 z-amino-pyridine (9.4 grams) is dissolved in k0 cc. of dry pyridine and 23.5 grams of p-acetylamino-benzene-sulphonyl chloride is added and the mixture heated on the steam bath. Water is then added andthe precipitated 2-(p-acetylamino-benzene-sulphonamido) pyridine, m. pt. 224 C., hydrolysed by boiling with cc. of

2N sodium hydroxide solution. The solution is cooled and made just acid to litmus by addition of 2N hydrochloric acid. The, precipitate of 2-(p-amino-benzene-sulphonamido)-pyridine is collected and recrystallised from water. Melting point C.

Example 2 To 16 grams of 6-amino-d"inaldine dissolved in 30 cc. of dry pyridine is dded 24 grams of melts at 272 C. v

This is converted to the amino compound by refluxing for 30 minutes with ten times its weight of 2N sodium hydroxide solution. On acidification to litmus, the base is obtained as a gum which rapidly crystallises. Alternatively, hydrolysis may be effected by heating under reflux p-acetylamino-benzene-sulphonyl-chloride. Aftwith 12 parts of dilute 15% hydrochloric acid for 1 hour and adding 50% sodium hydroxide solution until the solution is still acid to litmus but not to Congo red. The precipitated product is purified by solution in boiling alcohol and precipitation with water. Melting point 252 C. 2

Example 3 Emar nple 6 I 10 grams of p-nitro benzene-sulphonic" acid anhydride (prepared by the action of thionyl chloride on p-nitro-benzene-sulphonic acid dihydrate) areadded to a solution of 5 gramsoi 2-amino-pyridine in cc. of pyridine. The reaction mixture becomes warm and a precipitate of 2- (p-nitro-benzene-sulphonamido) pyridine is formed- The reaction mixture is diluted with water and dried. Melting point 195C.

This compound on reduction according to the method of Example 3 yields Z-(p-amino-benzenesulphonamidoi-pyridine.

Example 7 2.5 grams of 2-(p-amino-benzene-sulphonamide) -pyridine is suspended in 10 00.0! pyridine atjlaborato'ry temperature and 2 grams p-nitro-benzoyl chloride is added. The mixture is allowed to cool, diluted with water, and the precipitated 2ip-(p -nitro benzoyl amino) -benzene sulphonamidol pyridine filtered oil, washed To a solution of 4.7 grams of Z-amino-pyridine in 10 cc. of dry pyridine is added, with cooling,- l2 grammes of p-nitro-benzene-sulphonyl-chloride. An energetic reaction results: when this is over, the mixture is diluted with water, (200 cc.) and the precipitate of 2-(p-nitrobenzene sulphonamidol pyridine collected. Melting point 185 C.

Thenitro compound (1.4 grams) is dissolved in about 5 cc. of 2N sodium hydroxide solution and the suspension of Na salt formed on standing is added at 20 C. to a paste of ferrous hydroxide from 10 grams ferrous sulphate (hydrated) in cc. water and 3 grams sodium hydroxide in 5 cc. of water. hour) the mixture is filtered from ferric hydroxide and the filtrate acidified with acetic acid. The 2- (p-amino-benzene-sulphonamido) -pyridine melts at 190 C.

Example 4 After standing (1 16.5 grams of ,p-ch]orobenzene sulphonyl-.

' 13 hours at 150-175" C.

The excess of ammonia is removed and on dilution with water, Z-(p-amino-benzene-sulphonamido)-pyridin e is obtained and may be purified by crystallisation from water.

Example 5 A mixture of 21.4grams of p-acetylaminobenzene-sulphonamide, 13.0 grams of anhydrous potassium carbonate, 1.0 gram of copper powder and 15.8 grams of 2-bromo-pyridine is heated at 200-240 for 1 hour. The melt is dissolved in boiling water and filtered. On acidification with acetic acid, 2(p-acetylaminobenzene sulphon amido) -pyridine, M. Pt. 224 is obtained from which 2(p-aminobenzene-sulphonamido pyridine is formed by alkaline hydrolysis,

with water and dried. Melting point 272.

' Example 8 5.4 grams of 5-amino-8-methoxy-quinoline is dissolved in 10 cc. of pyridine, 7.3 "grams of p-acetylamino-benzene-su1phonyl chloride add and the mixture heated at. C. for a short time. Water is then added and the precipitated 5 (p acetylamino benzene sulphonamido)-8 methoxy q'uinoline filtered oil. and crystallised from dilute alcohol. Melting point185 C.

On hydrolysis oi this acetyl compound byboiling with 10 parts of 2. N sodium hydroxide followed by neutralisation to Congored, S-(p-aminobenzene-sulphonamido)-8 methoxy quinoline is obtained, which recrystallised from water, melts at 228-230 C.

Example 9 6.6 grams of 2: 6 diamino-pyridine is dissolved the reaction mixture has cooled, water is added" and the precipitated 2:6 di(p-acetylamino-benzene-sulphonamido) pyridine crystallised by solution in boiling alcoholic sodium hydroxide and reprecipitation with .hotacetic acid. Melting point 275 C. On hydrolysis by boiling .for 1' hour with 100. cc. of 2N caustic soda solution, and acidifying with dilute acetic acid 2:6 di(p-- amino-benzene-sulphonamido) -pyridine is pre-. cipitated. The crude product is purified by solu tion in boiling dilute sodium hydroxide and acidifying with dilute acetic acid, when the pure crys- Eeample 10 5; grams. of 2-hydroxy-4-methyl 7-aminotalline product, melting point 255C is obtained. I

quinolineare suspended in 25 ccuofpyridine,

6.8 grams. of p-acetyiamino-benzene-sulphcnyl chloride added, and the mixture heated'on the water bath .for a short time. On' dilution with water cc.) the precipitated 2 hydroxy-4- methyl-'I- (p-acetyl-amino-benzene sulphonamido) quinoline is, precipitated, filtered oil-washedwith water-and crystallised from dilute alcohol.

Melting point 304 C. Y

On hydrolysis of this compound by boiling for 1 hour with 10 parts of dilute caustic soda and subsequently acidifying with dilute acetic, acid 2 hydroxy-4 methyl 7-(p-amino-benzene-sulphonoamido) -quinoline is precipitated. After purification by solution in hot dilute sodiumhyfor 10 minutes.

of 2N caustic soda. solution.

droxide and re-precipitation by acidifying with hot acetic acid the Pure compound melts at 289 C. Example 11 by boiling with 10 parts of dilute sodium hydroxide solution and acidifying with dilute acetic acid 3 carboxy-2-(p-amino-benzene-sulphonamido) -pyridine is precipitated, which is obtained crystalline by solution in hot dilute sodium hydroxide and acidification with acetic acid. Melting point 176-1'79 C.

Example 12 10.8 grams of 2-amino-6-methyl pyridine is suspended in 20 cc. of pyridine, 23.5 grams of p-acetylamino benzene sulphonyl chloride added, and the mixture heated on the water bath on dilution with water crude 6-methyl-2-(p-acetylamino benzene sulphonamido) pyridine separates and is collected and after crystallisation from dilute acetic acid melts at 215 C. It is boiled with 150 cc. of 2N sodium hydroxide solution, filtered, and 150 cc. of 2N acetic acid added, and pure crystalline G-methyl- 2- (p-amino-benzene sulphonamido) pyridine thereby precipitated. Melting point 219 C. after recrystallisation from dilute acetic acid.

Example 13 amido) -quinoline is obtained. After crystallisation from dilute alcohol it melts at 200 C.

Example 14 4.7 grams of 2-amino pyridine are dissolved in 20 cc. of benzene, 12 grams of p-acetylaminobenzenesulphonyl chloride added and the mixture allowed to stand. The solid which separates is filtered, oil and boiled for 1 hour with 90 cc. n acidification with dilute acetic acid 2-(p-amino-benzene sulphonamido) -pyridine is precipitated and recrystallised from acetone. Melting point 190' C.

Example 15 2 grams of 2-(p-chlor-benzene-sulphonamido) pyridine (Example 4) or 2 grams of 2-(p-brombenzene-sulphonamido) pyridine (obtained in a similar manner from p-brom-benzene-sulphonyl-chloride and 2 amino-pyridine) is heated in a closed vessel with 8 cc. of a 30 per-cent aqueous solution of methylamine, and 0.1 gram of cuprous chloride for 12 hours at 150 C. After cooling, the reaction mixture is diluted with water and the precipitated 2 (p-methyl-amino-benzene-sulphonamido) pyridine purified by recrystallisation from alcohol. Melting point 154 C.

Example 16 9 grams of 2:4 dinitro-phenylamino-4 -su1- phonyl chloride prepared by the action of phosphorous pentachloride on the sodium salt of the corresponding sulphonic acid is added to a solution of 2.3 grams of 2-amino-pyridine in 20 cc. of pyridine. When the reaction is complete, water is added and the precipitated 2-(p-(2:4 dinitro-phenylamino) -benzene' sulphonamido) pyridine filtered off, washed, and crystallised from its solution in hot dilute alcoholic caustic soda by addition of 50 per cent. acetic acid. Melting point 230-233 C.

Example 17 5 grams of 2-(p-chlorbenzene-sulphonamido) pyridine are heated in a closed vessel with 20 cc. of a 30 per cent. aqueous solution of dimethylamine and 0.25 gram of cuprous chloride at 170 C. for 12 hours. After cooling, the contents of the tube are diluted with water and the precipitate extracted with cold dilute hydrochloric acid. Sodium acetate is then added to the acid extract and the precipitated 2-(p-dimethylamino-benzene sulphonamido)-pyridine recrystallised from alcohol. It melts at 218-220 C.

Example 18 Example 19 21.4 grams of p-acetylamino-benzene-sulphonamide, 13.5 grams of potassium carbonate, 1.0 gram of copper powder and 16.4 grams of 2-ch1oro-quinoline are heated together under reflux for 1 hours at 240-250 C. The cooled reaction massis extracted with boiling water filtered and the filtrate acidified with acetic acid when crude 2-(p-acetylamino-benzene-sulphonamido) quinoline is precipitated.

On hydrolysis by boiling with 160 cc. of 2N sodium hydroxide for 1 hour and acidifying the resulting solution with acetic acid 2-(p-aminobenzene-sulphonamido) quinoline is obtained which after re-solution in boiling dilute alkali and acidifying with hot acetic acid is obtained crystalline. Melting point 193-195 C.

Example 20 amido) -pyridine is dissolved in cc. of 2N sodium hydroxide solution and 8 cc. of dimethyl Example 22 9.6 grams of amino-quinaldine is dissolved in 27 cc. of pyridine and 11.8 grams of p-nitrobenzene-sulphonic-acid-anhydrideadded. When the reaction is complete about 500 cc. of water is added and. the precipitated G-(p-nitro-benzene sulphonamido) quinaldine is filtered oil an washed with water. i v

On reduction with ferrous hydroxide as described in Example 3, G-(p-amino-benzene-sulphonamido-) quinaldine, melting point 252 C., is obtained.

. I Example 23 6.4 grams of 2-amino-pyridine is dissolved in 50 cc. of pyridine and 22 grams of p-acetylbenzyl amino benzene sulphonyl chloride (British Patent 438,945) is added. When the reaction is complete the mixture is diluted with water and filtered, and the residual 2-(p-acetylbenzyl-amino-benzene-sulphonamido) pyridine crystallised from alcohol. Melting point 177 C.

The acetyl compound on boiling with 30% sodium hydroxide solution for 12 hours and acidifying with acetic acid yields 2-(p-benzylaminobenzene-sulphonamido) pyridine which after recrystallisation from alcohol melts at 200.

Example 24 a 9.7 gramsoi 1 aminodsoquinoline is dissolvedin 20 cc. of pyridine and l6 grams of p-acetylaminobenzene-sulphonyl chloride added, thetemperature being kept below 50 When the reaction is complete, water is added andthe solid separated by filtration. After purification by. dissolving in aqueousalcoholic sodium hydroxide solu-. tion and precipitationby-acidifying with acetic acid, crystalline 1-( pacetylamino-benzene-sulphonamido) -isoquinoline, melting point 225 C.

is obtained.

The acetyl compound on hydrolysis with 10 parts of boiling 2N sodium hydroxide solution for '1 hour, followed by acidification with acetic acid gives 1-(p-amino-benzene sulphonamido) isoquinoline. Melting point 263 C.

Example 25 Example 26 7 grams of p-diethylamino-azobenzene-p-sulphonyl chloride (prepared by the action of phosphorus pentachloride on'sodium p-diethyl-amino-azo-benzene sulphonate) is added to 1.9

grams of Z-amino-pyridine dissolved in 20 cc. of pyridine and after the reaction is over water is added. The precipitated Z-(p-diethylaminoazobenzene-p-sulphonamido)-pyridine is filtered off, washed with water, and dissolved in 5 parts of 2N sodium hydroxide solution. The solution is warmed to 304m 0. and solid sodium hydro-- s'ulphite added gradually until the red colour of the solution is discharged. Acetic acid is then added until the solution is faintly acid; .on concentration 2-(p-amino-benzene-sulphonamido)- pyridine separatesand is purified by recrystallisation from alcohol. Melting point 190 0.;

- Example .27 I

3 grams of p-acetyl-amino-benzene'-su1phonylchloride'are suspended in 5 cc. of chloroform and 1 gram of 2 amino-pyridine dissolved in 5 cc. of water is added. To themixture'is added '2grams of anhydrous sodium carbonate and the whole vigorously shaken at room temperature for 1 hour. The mixture is diluted with 20cc. off water, the chloroform layer together with any undissolved solid separated 01! and the' chloroform removed, by distillation. The residue is boiled with 25 cc. of 2N sodium hydroxide for 30 min-' utes and the solution precipitated by addition of hot glacial acetic acid until acid to litmus. The

crystalline precipitate of 2-(p-amino-benzene-' sulphonamido) rm'ridine is filteredofi' and recrystallised from acetone. It melts at 109-190'i C.

Example 281 Amixture of 4.6 grams of p-acetylamino-benzene-sulphon-methylamide, melting point 183' C., (obtained by the interaction of p-acetylaminobenzene-sulphonyl chloride and aqueous methylamine) 3.2 grams of 2-bromo'pyridine, '2.8grams of potassium carbonate and 0.2 powder is heated at 200 C. for 1 hour. The

cooled melt is extracted "with acetic acid."

and the filtered extract is concentrated whereupon 2-(p-acetylamino-benzene-sulphon-methylamido)-pyridine separates. Crystallised from dilute acetic acid, it melts at 231 C. Hydrolysis by boiling for 1 hour with 10 parts of 2N sodium hydroxide gives on acidification with acetic acid 2 (p amino 7 benzene sulphon methylamido) Crystallisedfrom alcohol it .melts at pyridine. 225 C.

Example 29, i

25 grams of phenyl-2-amino-pyridine-5-sulfonate is suspended in cc. of pyridine and 24 grams of p-acetylamino-benzene-sulphonyl-chlo+ ride, is added. After heating on a steam bath for 15 minutes, the mixtureis diluted with 500 cc. of water and the precipitated phenyl-2-(pacetylemino benzene sulphonamido) pyridine- 5-sulphonate is collected. crystallised from 50% acetic acid it melts at 175 185 C.

This ester on boiling for 1% hours with ten times its weight of 2N sodium hydroxide solution and addition, with cooling, of hydrochloric'acid until'just acid to Congo red gives 2-(p-aminobenzene sulphonamido) pyridine 5 sulphonic acid. Melting point 305 C. i i

' Example 30 9.4 grams of 2-amino-pyridine is dissolved in cc. of acetone and 11.6.gramsof p-acetylamino-benzene-sulpho'nyl chloride is added. The mixture is boiled under reflux for 1 hour, the acetone removed by distillation and the residue treated with water. 'The 2-(p-acetylamino-benzene-sulphonamido)-pyridine so formed is collected. It melts at 224 C. when crystallised from aqueous alcohol. 1

Example 31 To 9.4 grams of 2-amino-pyridine at 55 C. is. added 11.6 grams of p-acetylaminobenzenegram of; copper sulphonyl chloride. When the reaction is over the melt is dissolved in 150 cc. of 2N sodium hydroxide solution and the mixture is boiled under reflux for 1 hour. Acidification with acetic acid precipitates 2 (p amino benzene sulphonamidol-pyridine which melts at 190 C. when crystallised from aqueous alcohol.

Example 32 heated for 30 minutes at 180 C. The mixture is extracted with boiling water and filtered; acidification of the filtrate with acetic acid then gives 5 nitro 2 (p acetylamino benzene sulphonamido) -pyridine. Melting point 264 C.

Example 33 To a solution of 2.2 grams of 5-iodo-2-aminopyridine in 7 cc. of pyridine is added 2.4 grams of p acetylamino benzene sulphonyl chloride. When the reaction is over 70 cc. of water are added and the precipitate of 5-iodo-2-(p-acetylamino-benzene-sulphonamido)-pyridine is collected, washed with water and crystallised from 50% acetic acid. Melting point 234 C. Hydrolysis of this with 10 parts of 2N sodium hydroxide solution by boiling for 1 hour under reflux followed by addition of excess of 2N acetic acid gives 5-iodo-2- (p-aminobenzene-sulphonamido) pyridine. Purified by solution in boiling aqueous alcoholic sodium hydroxide followed by addition of boiling dilute acetic acid, it melts at 219 C.

Example {i4 4.3 grams of 2-methylamino-pyridine is dissolved in cc. of pyridine and 9.5 grams of p acetylamino benzene sulphonyl chloride is added. When the reaction mixture has cooled, 100 cc. of water are added and the precipitate of crude 2 (p acetylamino benzene sulphonmethylamido) -pyridine is collected, washed and crystallised from dilute acetic acid. Melting point 231 C.

Example 35 10 grams of 2-(p-aminobenzene-sulphonmethylamido)-pyridine (Example 21) is dissolved in cc. of 2N hydrochloric acid and 10 cc. of acetic anhydride followed by sufficient saturated sodium acetate solution to remove Congo red acidity are added. The precipitate of 2 (p acetylamino benzene sulphon methylamido)-pyridine is collected, washed and crystallised from dilute acetic acid. Melting point 231 C.

What We claim and desire to secure by Letters Patent is:

1. Method for producing Z-(p-aminobenzenesulphonamido)-pyridine by reacting 2-aminopyridine with a member of the group consisting of benzene-sulphonyl chloride and benzene-sulphonic acid anhydride containing a nitro group in the para position, and reducing the nitro group to an amino group.

2. The method for producing 2-(p-aminobenzene-sulphonamido)-pyridine which comprises reacting p nitro benzene sulphonyl chloride with 2-amino-pyridine in the presence of pyridine for the production of 2-(p-nitro-benzenesulphonamido)-pyridine and reducing the reaction product.

3. The method for producing Z-(p-aminobenzene-sulphonamido)-pyridine which comprises reacting p-nitro-benzene-sulphonic acid anhydride with 2-amino-pyridine in the presence of pyridine for the production of 2-(p-nitro-benzene-sulphonamido)-pyridine, and reducing the reaction product by the method according to claim 4.

4. In a method for producing 2-(p-aminobenzene-sulphonamido)-pyridine the steps which comprise dissolving 2-(p-nitro-benzene-sulphonamido)-pyridine in sodium hydroxide solution, allowing the solution to stand, adding the formed suspension of sodium salt at about 20 C. to a freshly made paste of ferrous hydroxide, allowing the mixture to stand, filtering the mixture and acidifying the filtrate.

ARTHUR JAMES EWINS. MONTAGUE ALEXANDER PHILLIPS. 

